1. Field of the Invention.
The present invention relates to novel improvements in battery monitors by which an individual cell in a wet cell battery may be monitored for variations in the level of electrolyte contained in the cell. More specifically, the invention relates to a universal electrolyte level indicator which may be attached to, and made part of, battery powered mobile equipment of all types for the purposes of providing a warning indication to the operator of the equipment that water needs to be added to the batteries contained therein.
2. Description of the Prior Art.
The prior art is replete with systems that indicate the electrolyte level within one or more cells of a wet cell battery. For example, U.S. Pat. Nos. 3,996,579; 3,891,465; 3,366,943; 2,779,015; 2,534,633 and 2,471,660 all describe systems for indicating battery electrolyte level drops using probes which are inserted into one or more cells and when the level of the fluid drops below a minimum acceptable level a circuit is completed which activates some type of warning device.
The prior art is likewise replete with devices that monitor state of charge (specific gravity) and/or temperature within a battery in addition to electrolyte level, as described in U.S. Pat. Nos. 4,625,201; 4,388,584; 4,329,406 and 4,247,188. The prior art also discloses the use of special materials to enhance the operational characteristics of the probes. German Patent No. 2,454,410 explains the use of tungsten carbide electrode accumulators, while British Patent No. 709,419 defines the use of platinum probes.
The prior art does not reveal an electrolyte level sensing device that may be used universally on batteries ranging from 6 vdc to 48 vdc without any modifications in circuit components or adjustments of any type whatsoever. Furthermore, the prior art has not addressed the special requirements associated with battery powered mobile equipment, such as the capability to monitor the level of electrolyte in a cell that is not electrochemically located between the positive and negative terminals of the battery used as the power source for the monitoring device. Additionally, no prior art was found that incorporates the use of double oscillators operating at different frequencies to produce a constant brightness of the indicating LED over a wide range of power source voltages in the context of the present invention as more fully described below.
Thus, notwithstanding the relatively substantial prior art in this particular field of technology, it is believed that the prior art neither teaches nor renders obvious the unique construction and universal operation of the electrolyte level indicator of the present invention.